package test;

//字符集合
import java.util.Scanner;
public class topic07 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String str = sc.nextLine();
        StringBuilder stringBuilder = new StringBuilder();
        for (int i = 0; i < str.length(); i++) {
            char cha = str.charAt(i);
            if (!stringBuilder.toString().contains(cha+"")){
                stringBuilder.append(cha);
            }
        }
        System.out.println(stringBuilder.toString());
    }
}
